A novel concept for the surgical anatomy of the perineal body

Ultrasonographic study of female perineal body and its supportive function on pelvic floor

Objectives

The study aimed to observe, measure the size and elastic value of perineal body (PB) and assess its association with levator hiatus.

Methods

Datasets were acquired in 45 nulliparous, 66 POP women and 70 postpartum women using ultrasound. The PB was measured in depth, height, and Young's modulus. The datasets were compared to assess whether there are some differences in the morphology, dimension and elastography modulus of PB among women. Pearson correlation analysis was used to evaluate the association between the morphology measurements (ΔValsalva-rest[v-r]), tissue mechanical properties (ΔValsalva-rest[v-r]) of the PB and levator hiatus area (ΔValsalva-rest[v-r]) to preliminarily explore whether PB can influence levator hiatus.

Results

Four representative manifestations of PB were presented in our study. Nulliparous women had smaller diameters and bigger Young's modulus while postpartum women had bigger diameters and smaller Young's modulus. POP and postpartum women had bigger levator hiatal distensibility and PB extensibility. There was no statistical association between PB measurements and levator hiatal area.

Conclusion

It is feasible to observe the morphology of PB and assess the dimension and elastography modulus by high-frequency ultrasound. The manifestations and measurements of PB are influenced by parity and long-term increased abdominal pressure. Our study preliminarily shows that PB has little effect on levator hiatus area.

Pelvic floor and perineal muscles: a dynamic coordination between skeletal and smooth muscles on pelvic floor stabilization

The purpose of this review is to present our researches on the pelvic outlet muscles, including the pelvic floor and perineal muscles, which are responsible for urinary function, defecation, sexual function, and core stability, and to discuss the insights into the mechanism of pelvic floor stabilization based on the findings. Our studies are conducted using a combination of macroscopic examination, immunohistological analysis, 3D reconstruction, and imaging. Unlike most previous reports, this article describes not only on skeletal muscle but also on smooth muscle structures in the pelvic floor and perineum to encourage new understanding. The skeletal muscles of the pelvic outlet are continuous, which means that they share muscle bundles. They form three muscle slings that pass anterior and posterior to the anal canal, thus serving as the foundation of pelvic floor support. The smooth muscle of the pelvic outlet, in addition to forming the walls of the viscera, also extends in three dimensions. This continuous smooth muscle occupies the central region of the pelvic floor and perineum, thus revising the conventional understanding of the perineal body. At the interface between the levator ani and pelvic viscera, smooth muscle forms characteristic structures that transfer the lifting power of the levator ani to the pelvic viscera. The findings suggest new concepts of pelvic floor stabilization mechanisms, such as dynamic coordination between skeletal and smooth muscles. These two types of muscles possibly coordinate the direction and force of muscle contraction with each other.

Comparison of the Perineal Body Between Chinese Women With Pelvic Organ Prolapse and Women With Normal Support by Magnetic Resonance Imaging With 3-Dimensional Reconstruction

OBJECTIVE

This study aimed to determine whether the perineal body (PB) is different between women with and without prolapse and to analyze its association with prolapse.

METHODS

This cross-sectional observational study was performed in a tertiary-level urology department and included patients with stage II-IV pelvic organ prolapse (POP) and normal controls with all points 1 cm or more above the hymen. The patients underwent supine midsagittal magnetic resonance imaging (MRI) at rest and during the maximum Valsalva maneuver. Perineal mobility and PB length, height, perimeter, and area were measured; in addition, the genital hiatus and PB were measured according to the definition of the Pelvic Organ Prolapse Quantification system. Univariate associations of POP with characteristics were assessed using the chi-square test or Fisher exact test for categorical variables and the t test for continuous variables. Multivariate logistic regression analysis was used to estimate the adjusted odds ratios and 95% confidence intervals.

RESULTS

Seventy-two controls and 130 patients were analyzed. The PB length, height, and area measurements were significantly lower in the POP group. The perineal mobility in different directions was significantly higher in the POP group. Multivariate analysis demonstrated that the PB area and perineal mobility in the ventral-dorsal and cranio-caudal directions were associated with POP.

CONCLUSIONS

Our data suggest that a smaller PB area and greater dorsal or caudal mobility are associated with prolapse.

Long-standing groin pain syndrome in athletic women: a multidisciplinary assessment in keeping with the italian consensus agreement

BACKGROUND

Long-standing groin pain syndrome (LSGPS) is a form of groin pain syndrome in which the cohort of symptoms reported by patients is experienced for a long period, typically for over 12 weeks, and is recalcitrant to any conservative therapy. The aim of this prospective epidemiological study was to describe the clinical causes of LSGPS in 37 female athletic subjects in Italy through the Groin Pain Syndrome Italian Consensus Conference on terminology, clinical evaluation and imaging assessment in groin pain in athletes classification and guidelines.

METHODS

Thirty-seven female athletes affected by LSGPS were evaluated following the guidelines issued by the Groin Pain Syndrome Italian Consensus Conference on terminology, clinical evaluation and imaging assessment of groin pain in athletes.

RESULTS

In the considered population, each patient presented only one pathological cause for LSGPS. The most frequent aetiologies were inguinal pathologies (54.05% of the cases), acetabular labrum tear (18.92%) and pelvic floor disorders (8.11%). Adductor tendinopathy represented only 2.70% of cases.

CONCLUSIONS

Female athletic patients affected by LSGPS show a similar incidence of inguinal and hip pathologies as in male populations. However, these clinical situations do not seem to be associated in women unlike in the male population. This difference is probably due to particular anatomical differences related to gender. For this reason, women affected by LSGPS represent an important subset of patients. Moreover, adductor tendinopathy is probably overrated as an etiopathogenetic source of LSGPS in women.

The effect of the birth method on changes of the prepartum and postpartum dimensions of perineal body

OBJECTIVE

The perineal body is critical for maintaining the integrity of the pelvic floor, especially in females as it can be injured during vaginal delivery. This study aimed to evaluate the effect of childbirth on perineal body dimensions by using a transperineal 2D ultrasound.

STUDY DESIGN

This prospective cohort study was performed in a tertiary obstetric care center. A total of 172 term pregnant women who delivered either by cesarean section or vaginal delivery were enrolled in the study. All demographic data and information were collected prospectively. The perineal body was measured in length, height, perimeter, and area. Mode of delivery was classified into four categories, including prelabor cesarean section, cesarean section during the first stage of labor, the first vaginal delivery, and more than one previously vaginal delivery. A postpartum evaluation was performed after 6 weeks.

RESULTS

Among the 172 women, 40 (23.3 %) had a history of cesarean section (CS) and they delivered with scheduled CS, 40 (23.3 %) women delivered by primary CS during active labor, 48 (27.9 %) women had the first vaginal delivery, 44 (25.6 %) women who delivered vaginally had a history of at least one vaginal delivery. The postpartum perineal body measurements were significantly lower in terms of length, perimeter, and area in all pregnancy groups.

CONCLUSION

Pregnancy and delivery change perineal body dimensions, significantly. Cesarean section does not completely protect against changes in perineal body morphology.

Midline and Mediolateral Episiotomy: Risk Assessment Based on Clinical Anatomy

Episiotomy is the surgical incision of the vaginal orifice and perineum to ease the passage of an infant’s head while crowning during vaginal delivery. Although episiotomy remains one of the most frequently performed surgeries around the world, short- and long-term complications from the procedure are not uncommon. We performed midline and mediolateral episiotomies with the aim of correlating commonly diagnosed postepisiotomy complications with risk of injury to perineal neuromuscular and erectile structures. We performed 61 incisions on 47 female cadavers and dissected around the incision site. Dissections revealed that midline incisions did not bisect any major neuromuscular structures, although they did increase the risk of direct and indirect injury to the subcutaneous portion of the external anal sphincter. Mediolateral incisions posed greater risk of iatrogenic injury to ipsilateral nerve, muscle, erectile, and gland tissues. Clinician discretion is advised when weighing the potential risks to maternal perineal anatomy during vaginal delivery when episiotomy is indicated. If episiotomy is warranted, an understanding of perineal anatomy may benefit diagnosis of postsurgical complications.

The series of smooth muscle structures in the pelvic floors of men: Dynamic coordination of smooth and skeletal muscles

Introduction

Recent studies have revealed the extended nature of smooth muscle structures in the pelvic floor, revising the conventional understanding of the “perineal body.” Our aim was to clarify the three‐dimensional configuration and detailed histological properties of the smooth muscle structures in the region anterior to the rectum and anal canal in men.

Materials and methods

Four male cadavers were subjected to macroscopic and immunohistological examinations. The pelvis was dissected from the perineal side, as in the viewing angle during transperineal surgeries. Serial transverse sections of the region anterior to the rectum and anal canal were stained with Masson's trichrome and immunohistological stains to identify connective tissue, smooth muscle, and skeletal muscle.

Results

There was a series of smooth muscle structures continuous with the longitudinal muscle of the rectum in the central region of the pelvic floor, and three representative elements were identified: the anterior bundle of the longitudinal muscle located between the external anal sphincter and bulbospongiosus; bilateral plate‐like structures with transversely‐oriented and dense smooth muscle fibers; and the rectourethral muscle located between the rectum and urethra. In addition, hypertrophic tissue with smooth muscle fibers extended from the longitudinal muscle in the anterolateral portion of the rectum and contacted the levator ani.

Conclusions

The series of smooth muscle structures had fiber orientations and densities that differed among locations. The widespread arrangement of the smooth muscle in the pelvic floor suggests a mechanism of dynamic coordination between the smooth and skeletal muscles.

The histological microstructure and in vitro mechanical properties of pregnant and postmenopausal ewe perineal body

OBJECTIVE

The mechanical properties and microstructure of the perineal body are important for the improvement of numerical models of pelvic organs. We determined the mechanical parameters and volume fractions of the ewe perineal body as an animal model.

METHODS

The 39 specimens of 13 pregnant swifter ewes delivering by cesarean section (aged 2 years, weight 61.2 ± 6.2 kg (mean ± standard deviation) and 24 specimens of 8 postmenopausal swifter ewes 150 days after surgical ovariectomy (aged 7 years, 58.6 ± 4.6 kg)) were loaded uniaxially to determine Young's moduli of elasticity in the small (E0) and large (E1) deformation regions, and ultimate stresses and strains. The 63 adjacent tissue samples were processed histologically to assess volume fractions of smooth and skeletal muscle, adipose cells, elastin, and type I collagen using a stereological point testing grid. We compared the structural and mechanical differences along the ewe perineal body, and between pregnant and postmenopausal groups.

RESULTS

The pregnant/postmenopausal perineal body was composed of smooth muscle (12/14%; median), skeletal muscle (12/16%), collagen (10/23%), elastin (8/7%), and adipose cells (6/6%). The E0 was 37/11 kPa (median), E1 was 0.97/1.04 MPa, ultimate stress was 0.55/0.59 MPa, and ultimate strain was 0.90/0.87 for pregnant/postmenopausal perineal body. The perineal body showed a structural and mechanical stability across the sites. The pregnant ewes had a higher amount of skeletal muscle, higher E0, and a less amount of collagen when compared with postmenopausal ewes.

CONCLUSIONS

The data can be used as input for models simulating vaginal delivery, pelvic floor prolapsed, or dysfunction.

The histological microstructure and in vitro mechanical properties of the human female postmenopausal perineal body

OBJECTIVE

The perineal body connects muscles from the pelvic floor and is critical for support of the lower part of the vagina and proper function of the anal canal. We determined mechanical parameters and volume fractions of main components of the human female postmenopausal perineal body.

METHODS

The specimens were taken from 15 fresh female cadavers (age 74 ± 10, mean ± standard deviation). Seventy-five specimens from five regions of the perineal body were processed histologically to assess volume fractions of tissue components using stereological point testing grid. Fifteen specimens taken from the midline region were loaded uniaxially with 6 mm/min velocity until tissue rupture to determine Young's modulus of elasticity, ultimate stresses, and strains.

RESULTS

The perineal body was composed of collagen (29%), adipose cells (27%), elastin (7%), smooth muscle (11%), and skeletal muscle (3%). The residual tissue (19%) constituted mostly peripheral nerves, lumina of blood vessels, fibroblasts, and fibrocytes. Young's modulus of elasticity at midline region was 18 kPa (median) at small and 232 kPa at large deformations, respectively. The ultimate stress was 172 kPa and the ultimate strain was 1.4.

CONCLUSIONS

We determined the structural and mechanical parameters of the perineal body. The resultant data could be used as input for models simulating pelvic floor prolapse or dysfunction.

Three muscle slings of the pelvic floor in women: an anatomic study

The region anterior to the anal canal in women is composed of intertwined smooth and skeletal muscles. The present study aimed to clarify skeletal muscle morphology in the anterior region of the anal canal. The pelvic floor muscles of 28 pelvic halves from 16 female cadavers (mean age 79.75 years) were dissected from the inferior aspect to examine the perineal muscles, followed by midline transection and dissection from the inner surface to examine the pelvic outlet muscles. The bulbospongiosus muscle was found to be attached to the lateral surface of the external anal sphincter. The superficial transverse perineal muscle crossed superiorly to the bulbospongiosus and coursed medially toward its contralateral muscle bundle deep to the anterior portion of the external anal sphincter. The superficial transverse perineal muscle formed the middle sling. From the medial aspect, the anterior part of the levator ani was divided into anterior and posterior bundles to form the anterior and posterior slings, respectively. This study proposes that three muscular slings could be important in supporting the pelvic floor in women. In addition, this study shows that the anterior skeletal muscular wall of the anal canal is composed of the anterior muscle bundle of the levator ani, superficial transverse perineal, and proper external anal sphincter muscles.

Ultrasound imaging of the perineal body: a useful clinical tool

Introduction and hypothesis

The perineal body is a fibromuscular pyramidal structure located between the vagina and the anus. It has been difficult to image because of its small size and anatomical location. This study used 2D transperineal ultrasound to measure the perineal body and assess whether there is an association with prolapse.

Methods

An observational, cross-sectional study was carried out in a tertiary level Urogynaecology department and included prolapse patients and healthy nulliparous volunteers (control group). This was a clinical assessment, including POP-Q and trans-perineal 2D ultrasound measurement of the perineal body height, length, perimeter, and area. Parametric tests were used, as the data were normally distributed. Results are reported as mean and 95% confidence interval (±95% CI).

Results

A total of 101 participants were recruited of which 22 were nulliparous healthy volunteers. Mean perineal body measurements in controls were height 22.5 ± 3.3 mm, length 17.4 ± 2.7 mm, perimeter 7.5 ± 0.9 mm, and area 2.8 ± 0.38 cm². Perineal body measurements in 79 prolapse patients: height 16.9 ± 1.7 mm, length 16.0 ± 1.4 mm, perimeter 6.5 ± 0.5 mm and area 2.1 ± 0.5 cm². A small perineal body was strongly associated with posterior compartment prolapse (paired t test, p < 0.0001) and wider POP-Q GH (paired t test, p = 0.0003). Surprisingly, Pelvic Organ Prolapse Quantification Perineal Body (POP-Q PB) of the two groups was not significantly different. A perineal body mid-sagittal area of less than 2.4 cm² has been shown to be associated strongly with posterior compartment prolapse.

Conclusions

It is possible to measure the perineal body on 2D ultrasound. This technique facilitates the objective diagnosis of perineal deficiency. POP-Q PB does not predict the length or area of the perineal body.

Novel simulations to determine the impact of superficial perineal structures on vaginal delivery

This study's aim was to determine whether the inclusion of superficial perineal structures in a finite-element simulation of vaginal delivery impacts the pubovisceral muscle and perineal body, two common sites of birth-related injury. The hypothesis, inferred from prevailing literature, was that these structures would have minimal influence (differences less than ±10%). Two models were made using the Visible Human Project's female cadaver to create a rigid, fixed pelvis, musculature held by spring attachments to that pelvis, and a rigid, ellipsoidal fetal head prescribed with an inferior displacement to simulate delivery. Injury site stretch ratios and fetal head and perineal body displacements and angles of progression were compared between the Omitted Model (which excluded the superficial perineal structures as is common practice) and the Included Model (which included them). Included Model stretch ratios were +107%, -9.84% and -14.6% compared to Omitted Model perineal body and right and left pubovisceral muscles, respectively. Included Model peak perineal body inferior displacement was +72.5% greater while similar anterior-posterior displacements took longer to reach. These results refute our hypothesis, suggesting superficial perineal structures impact simulations of vaginal delivery by inhibiting perineal body anterior-posterior displacement, which stretches and inferiorly displaces the perineal body.

Male and female anatomical homologies in the perineum of the dog (Canis familiaris)

Understanding the homologies between male and female perineal structure helps both evolutionary biologists and clinicians better understand the evolution and anatomy of canines. Domestic dogs (Canis familiaris) play an important role in human society, and canine perineal anatomy is important for maintaining dogs’ reproductive health for successful breeding and a wide variety of pathologies. Here, we investigate homologies between male and female perineal structure, identifying structures based on common function, anatomical relationships and attachments. In this investigation we dissected 21 male and female large‐breed dogs. We find broad structural homologies between male and female dogs related to erection, micturition and defecation, including muscles, fasciae and erectile tissue. Using these homologies will help anatomists and clinicians interpret the anatomical organization of the perineum, a notoriously difficult area of anatomy.

Connectivity of the Superficial Muscles of the Human Perineum: A Diffusion Tensor Imaging-Based Global Tractography Study

Despite the importance of pelvic floor muscles, significant controversy still exists about the true structural details of these muscles. We provide an objective analysis of the architecture and orientation of the superficial muscles of the perineum using a novel approach. Magnetic Resonance Diffusion Tensor Images (MR-DTI) were acquired in 10 healthy asymptomatic nulliparous women, and 4 healthy males. Global tractography was then used to generate the architecture of the muscles. Micro-CT imaging of a male cadaver was performed for validation of the fiber tracking results. Results show that muscles fibers of the external anal sphincter, from the right and left side, cross midline in the region of the perineal body to continue as transverse perinea and bulbospongiosus muscles of the opposite side. The morphology of the external anal sphincter resembles that of the number '8' or a "purse string". The crossing of muscle fascicles in the perineal body was supported by micro-CT imaging in the male subject. The superficial muscles of the perineum, and external anal sphincter are frequently damaged during child birth related injuries to the pelvic floor; we propose the use of MR-DTI based global tractography as a non-invasive imaging technique to assess damage to these muscles.

MRI of anal canal: normal anatomy, imaging protocol, and perianal fistulas: Part 1

Anal complaints are very common in the general population and are caused by a variety of disorders mostly benign in nature. The aim of this article is to provide the radiologist with a detailed description of the MRI anatomy and technique, and an overview of the various diseases most commonly presenting with anal pain, by descriptions and illustrative examples of MRI features of each entity.

Reorganization of mammalian body wall patterning with cloacal septation

Septation of the cloaca is a unique mammalian adaptation that required a novel reorganization of the perineum–the caudal portion of the trunk body wall not associated with the hindlimb. Fish, the basal vertebrates, separate ventrolateral body wall musculature of the trunk into two discrete layers, while most tetrapods expand this pattern in the thorax and abdomen into four. Mammals, the only vertebrate group to divide the cloaca into urogenital and anorectal portions, exhibit complex muscle morphology in the perineum. Here we describe how perineal morphology in a broad sample of mammals fits into patterning of trunk musculature as an extension of the four-layer ventrolateral muscular patterning of the thorax and abdomen. We show that each perineal muscle layer has a specific function related to structures formed by cloacal septation. From superficial to deep, there is the subcutaneous layer, which regulates orifice closure, the external layer, which supplements both erectile and micturition function, the internal layer, which provides primary micturition and defecation regulation, and the transversus layer, which provides structural support for pelvic organs. We elucidate how the four-layer body wall pattern, restricted to the non-mammal tetrapod thorax and abdomen, is observed in the mammalian perineum to regulate function of unique perineal structures derived from cloacal septation.

Bilateral plication of the puborectal muscles: A new surgical concept for treating vulvar widening

OBJECTIVES

This study describe a new myorraphy technique by bilateral plication of the puborectalis bundles (PRP) of the levator ani muscle to treat vulvovaginal widening. The aim of this work was to report our preliminary experience in terms of morbidity and results (anatomical and functional) in the short and medium term.

MATERIALS AND METHODS

This single centre retrospective study concerned 69 women who underwent PRP between January 2011 and December 2014. The main criterion for judging success was the GH before and after surgery (Genital Hiatus in the POP-Q classification: Pelvic Organ Prolapse Quantification System). The secondary criteria were the quality of sexual intercourse and the morbidity.

RESULTS

The average GH post-surgery was 31, 35 and 35mm at 6 weeks, 6 and 12 months respectively compared to 65±5mm preoperatively (P<0.00001). Among the 27 patients who were sexually active prior to surgery, 18.52% deemed the quality of sexual intercourse satisfactory. After surgery, more than 88% of the patients observed an improvement (P<0.00001). After the surgery the reported rate of minor complications was under 3%.

CONCLUSION

This preliminary study of PRP confirms the feasibility of the procedure, its low morbidity and the stability of the anatomical outcomes at 12 months.

Myotonometry Reliably Measures Muscle Stiffness in the Thenar and Perineal Muscles

Purpose: The authors investigated the reliability of myotonometry-measured muscle tone in the thenar and perineal muscles. Methods: Participants were women aged 18-50 years who were asymptomatic for thumb and pelvic floor dysfunction (interrater study n=20; intrarater study n=43) or who were symptomatic for vulvodynia (interrater study n=14; intrarater study n=32). Mechanical properties (stiffness, frequency, decrement, relaxation time, and creep) of the muscles were measured using a myotonometer (MyotonPRO) while the muscles were in a relaxed state. Measures were performed twice by two assessors. Intra- and interrater reliability were determined using intra-class correlation coefficients (ICCs) and absolute reliability using the standard error of measurement and a minimum detectable change. Results: The primary property of interest, muscle stiffness, showed very good interrater (ICC 0.85-0.86) and intrarater (ICC 0.82-0.88) reliability in the thenar eminence. In the perineal muscles, reliability results ranged from good to very good for interrater (ICC 0.70-0.86) and intrarater (ICC 0.80-0.91) reliability for muscle stiffness. Absolute reliability was confirmed, with all measures showing minimal variance. Conclusions: Muscle stiffness of the smaller muscles of the body can be reliably measured using the MyotonPRO. The device could be used as a reference standard in the development of a digital palpation scale that would facilitate accurate diagnosis of muscle tone.

Architectural differences in the anterior and middle compartments of the pelvic floor of young-adult and postmenopausal females

The pelvic floor guards the passage of the pelvic organs to the exterior. The near-epidemic prevalence of incontinence in women continues to generate interest in the functional anatomy of the pelvic floor. However, due to its complex architecture and poor accessibility, the classical 'dissectional' approach has been unable to come up with a satisfactory description, so that many aspects of its anatomy continue to raise debate. For this reason, we opted for a 'sectional' approach, using the Chinese Visible Human project (four females, 21-35 years) and the Visible Human Project (USA; one female, 59 years) datasets to investigate age-related changes in the architecture of the anterior and middle compartments of the pelvic floor. The puborectal component of the levator ani muscle defined the levator hiatus boundary. The urethral sphincter complex consisted of a circular proximal portion (urethral sphincter proper), a sling that passed on the vaginal wall laterally to attach to the puborectal muscle (urethral compressor), and a circular portion that surrounded the distal urethra and vagina (urethrovaginal sphincter). The exclusive attachment of the urethral sphincter to soft tissues implies dependence on pelvic-floor integrity for optimal function. The vagina was circular at the introitus and gradually flattened between bladder and rectum. Well-developed fibrous tissue connected the inferior vaginal wall with urethra, rectum and pelvic floor. With eight-muscle insertions, the perineal body was a strong, irregular fibrous node that guarded the levator hiatus. Only loose areolar tissue comprising a remarkably well developed venous plexus connecting the middle and superior parts of the vagina with the lateral pelvic wall. The posterolateral boundary of the putative cardinal and sacrouterine ligaments coincided with the adventitia surrounding the mesorectum. The major difference between the young-adult and postmenopausal pelvic floor was the expansion of fat in between the components of the pelvic floor. We hypothesize that accumulation of pelvic fat compromises pelvic-floor cohesion, because the pre-pubertal pelvis contains very little fibrous and adipose tissue, and fat is an excellent lubricant.

The anatomy of the perineal body in relation to abdominoperineal excision for low rectal cancer

AIM

Dissection of the perineal body (PB) during abdominoperineal excision (APE) for low rectal cancer is often difficult due to the lack of a natural plane of dissection. Understanding the PB and its relation to the anorectum is essential to permit safe dissection during the perineal phase of the operation and avoid damage to the anorectum and urogenital organs. This study describes the anatomy and histology of the PB relevant to APE.

METHOD

Six human adult cadaver pelvic exenteration specimens (three male, three female) from the Leeds GIFT Research Tissue Programme were studied. Paraffin-embedded mega-blocks were produced and serially sectioned at 50- and 250-μm intervals. Sections were stained by immunohistochemistry to show collagen, elastin and smooth muscle.

RESULTS

The PB was cylindrically shaped in the male specimens and wedge-shaped in the female ones. Although centrally located between the anal and urogenital triangles, it was nearly completely formed by muscle fibres derived from the rectal muscularis propria. Thick bundles of smooth muscle, mostly arising from the longitudinal muscle, inserted into the PB and levator ani muscle (LAM). The recto-urethralis muscle originated from the PB and separated the anterolateral PB from the urogenital organs.

CONCLUSION

Smooth muscle fibres derived from the rectal muscularis propria extend into the PB and LAM and appear to fix the anorectum. Dissection of the PB during APE is safe only when the smooth muscle fibres that extend into the PB are divided.

Transverse Perineal Support: A Novel Surgical Treatment for Perineal Descent in Patients With Obstructed Defecation Syndrome

BACKGROUND

We hypothesized that pathological perineal descent may be responsible for the failure of operations for obstructed defecation syndrome and that correcting excessive perineal descent may improve the outcome in this group of patients.

OBJECTIVE

The purpose of this study was to report the short-term preliminary results of a novel surgical procedure, transverse perineal support, for the correction of pathological perineal descent.

DESIGN

This was a prospective, uncontrolled, open-label study.

SETTINGS

The study was conducted in a hospital and a university center.

PATIENTS

Among 25 patients observed with failure of previous surgery for obstructed defecation syndrome, 12 with pathological perineal descent underwent transverse perineal support, were followed-up at 6 months, and constituted the object of analysis.

INTERVENTIONS

The surgical procedure was performed positioning a porcine dermal implant just above the perineum superficial fascia sutured to the periosteum membrane of ischiatic tuberosities at the insertion of the superficial transverse perineal muscle.

MAIN OUTCOME MEASURES

The main outcome measures were obstructed defecation syndrome score and x-ray and magnetic resonance defecographic imaging evaluation of perineal descent and anorectal manometric parameters.

RESULTS

The postoperative median obstructed defecation syndrome score was 7.0 (range, 3-8), showing a statistically significant difference if compared with the preoperative score of 13.5 (range, 9-18; p = 0.0005). The mean postoperative maximum intrarectal pressure was 69.4 ± 11.1 mm Hg, significantly higher than the preoperative pressure of 45.9 ± 12.8 mm Hg (p < 0.0001). At postoperative x-ray and magnetic resonance imaging defecography, the mean fixed and dynamic perineal descents were significantly lower than the preoperative descents (p = 0.02 for fixed perineal descent and p = 0.0004 for dynamic perineal descent). Of the 4 patients (33.3%) with preoperative pathological dynamic perineal descent, only 1 showed a persistent pathological dynamic perineal descent. No early or late complication was observed.

LIMITATIONS

The study was limited by its small size and short follow-up time.

CONCLUSIONS

Transverse perineal support appears to be a promising, safe, and effective procedure in the treatment of obstructed defecation syndrome associated with pathological perineal descent (see Video, Supplemental Digital Content 1, http://links.lww.com/DCR/A225).

Perineal body anatomy seen by three-dimensional endovaginal ultrasound of asymptomatic nulliparae

AIM

The perineal body (PB) plays an important role in supporting the pelvic floor and the posterior vaginal wall, but its attachments and relationships are still debated. This study aimed to assess the normal anatomy of the PB using high-resolution three-dimensional endovaginal ultrasound (3D-EVUS) in asymptomatic nulliparae.

METHOD

To validate the identification of perineal structures, 3D-EVUS was initially performed on nulliparous cadavers. Fresh frozen pelves were prepared and echogenic structures thought to be the PB, the external anal sphincter, the superficial and deep transverse perineii, pubovaginalis, puboperinealis, puboanalis, puborectalis and iliococcygeus muscles were tagged with biopsy needles, and marked with indigo carmine dye for localization during dissection. In the second part of the study, consecutive asymptomatic nulliparae were prospectively imaged with the same ultrasound modality. Interrater reproducibility was assessed off-line from stored 3D US volumes using a standardized technique.

RESULTS

Five fresh frozen pelves and 44 asymptomatic nulliparae were assessed with 3D-EVUS. The PB was seen as an ovoid structure of mixed echogenicity between the rectum and vagina. It appeared to be divided into a superficial level, in contact with the external anal sphincter, the bulbospongiousus and the superficial transverse perineii muscle and a deep level, in contact with puboperinealis and puboanalis muscles. Interobserver repeatability was excellent for the measurements of PB height [intraclass correlation coefficient (ICC) 0.927], PB depth (ICC 0.969) and PB width (ICC 0.932).

CONCLUSION

The PB is divided into two levels with different anatomical relationships with the pelvic floor muscles. 3D-EVUS yields reproducible assessment of this complex structure.

Cystocele and functional anatomy of the pelvic floor: review and update of the various theories

INTRODUCTION AND HYPOTHESIS

We updated anatomic theories of pelvic organ support to determine pathophysiology in various forms of cystocele.

METHODS

PubMed/MEDLINE, ScienceDirect, Cochrane Library, and Web of Science databases were searched using the terms pelvic floor, cystocele, anatomy, connective tissue, endopelvic fascia, and pelvic mobility. We retrieved 612 articles, of which 61 matched our topic and thus were selected. Anatomic structures of bladder support and their roles in cystocele onset were determined on the international anatomic classification; the various anatomic theories of pelvic organ support were reviewed and a synthesis was made of theories of cystocele pathophysiology.

RESULTS

Anterior vaginal support structures comprise pubocervical fascia, tendinous arcs, endopelvic fascia, and levator ani muscle. DeLancey's theory was based on anatomic models and, later, magnetic resonance imaging (MRI), establishing a three-level anatomopathologic definition of prolapse. Petros's integral theory demonstrated interdependence between pelvic organ support systems, linking ligament-fascia lesions, and clinical expression. Apical cystocele is induced by failure of the pubocervical fascia and insertion of its cervical ring; lower cystocele is induced by pubocervical fascia (medial cystocele) or endopelvic fascia failure at its arcus tendineus fasciae pelvis attachment (lateral cystocele).

CONCLUSIONS

Improved anatomic knowledge of vaginal wall support mechanisms will improve understanding of cystocele pathophysiology, diagnosis of the various types, and surgical techniques. The two most relevant theories, DeLancey's and Petros's, are complementary, enriching knowledge of pelvic functional anatomy, but differ in mechanism. Three-dimensional digital models could integrate and assess the mechanical properties of each anatomic structure.

3D Topography of the Young Adult Anal Sphincter Complex Reconstructed from Undeformed Serial Anatomical Sections

Background

Pelvic-floor anatomy is usually studied by artifact-prone dissection or imaging, which requires prior anatomical knowledge. We used the serial-section approach to settle contentious issues and an interactive 3D-pdf to make the results widely accessible.

Method

3D reconstructions of undeformed thin serial anatomical sections of 4 females and 2 males (21–35y) of the Chinese Visible Human database.

Findings

Based on tendinous septa and muscle-fiber orientation as segmentation guides, the anal-sphincter complex (ASC) comprised the subcutaneous external anal sphincter (EAS) and the U-shaped puborectal muscle, a part of the levator ani muscle (LAM). The anococcygeal ligament fixed the EAS to the coccygeal bone. The puborectal-muscle loops, which define the levator hiatus, passed around the anorectal junction and inserted anteriorly on the perineal body and pubic bone. The LAM had a common anterior attachment to the pubic bone, but separated posteriorly into puborectal and “pubovisceral” muscles. This pubovisceral muscle was bilayered: its internal layer attached to the conjoint longitudinal muscle of the rectum and the rectococcygeal fascia, while its outer, patchy layer reinforced the inner layer. ASC contraction makes the ano-rectal bend more acute and lifts the pelvic floor. Extensions of the rectal longitudinal smooth muscle to the coccygeal bone (rectococcygeal muscle), perineal body (rectoperineal muscle), and endopelvic fascia (conjoint longitudinal and pubovisceral muscles) formed a “diaphragm” at the inferior boundary of the mesorectum that suspended the anorectal junction. Its contraction should straighten the anorectal bend.

Conclusion

The serial-section approach settled contentious topographic issues of the pelvic floor. We propose that the ASC is involved in continence and the rectal diaphragm in defecation.

Live anatomy of the perineal body in patients with third-degree rectocele

AIM

In many pelvic floor disorders, the perineal body is damaged or destroyed. There is still a considerable variation in anatomical descriptions of the perineal body and even more debate with regard to its attachments and relationships. Cadaveric dissections do not always reflect the functional behaviour of structures in the pelvis and description of live anatomy on imaging studies is not always reliable. This study aimed to define the anatomy of the perineal body in patients with rectocele during the live dissection required for minimally invasive surgical repair.

METHOD

From January 2007 to December 2009 consecutive patients requiring surgery for third-degree rectocele and symptoms of obstructed defaecation were recruited. Participants underwent dissection of the perineal body, rectum and vagina preliminary to a tissue fixation system, an operation which inserts a tensioned tape to repair the perineal body.

RESULTS

Thirty Caucasian female patients, mean age 61 (range 47-87) years, mean parity 2.6 (range 1-5), were included. Live dissection demonstrated that the perineal body was divided into two parts, joined by a stretched central part, anchored laterally by the deep transverse perineii muscle to the descending ramus of the pubic bone. The mean longitudinal length of the perineal body was 4.5 (3.5-5.5) cm, accounting for 50% of the posterior vaginal support.

CONCLUSION

In women with low rectocele, the perineal body appears to be divided into two parts, severely displaced behind the ischial tuberosities.

Normal vulvovaginal, perineal, and pelvic anatomy with reconstructive considerations

A thorough insight into the female genital anatomy is crucial for understanding and performing pelvic reconstructive procedures. The intimate relationship between the genitalia and the muscles, ligaments, and fascia that provide support is complex, but critical to restore during surgery for correction of prolapse or aesthetic reasons. The external female genitalia include the mons pubis, labia majora and minora, clitoris, vestibule with glands, perineal body, and the muscles and fascia surrounding these structures. Through the perineal membrane and the perineal body, these superficial vulvar structures are structurally related to the deep pelvic muscle levator ani with its fascia. The levator ani forms the pelvic floor with the coccygeus muscle and provides vital support to all the pelvic organs and stability to the perineum. The internal female genital organs include the vagina, cervix, uterus, tubes, and ovaries with their visceral fascia. The visceral fascia also called the endopelvic fascia, surrounds the pelvic organs and connects them to the pelvic walls. It is continuous with the paraurethral and paravaginal fascia, which is attached to the perineal membrane. Thus, the internal and external genitalia are closely related to the muscles and fascia, and work as one functioning unit.

Influence of perineal prostatectomy on anal continence

OBJECTIVE

Perineal prostatectomy has been proposed as a less invasive and safe procedure, but the risk of anal incontinence has been studied. This study aimed to evaluate the effects of perineal access on anal continence mechanisms after perineal prostatectomy.

METHODS

From August 2008 to May 2009, twenty three patients underwent perineal prostatectomy. These patients were evaluated before surgery and eight months postoperatively using the Cleveland Clinic Anal Incontinence Score, the Fecal Incontinence Quality of Life Score, and anorectal manometry.

RESULTS

The mean age of the subjects was 65 (range, 54-72) years, and the mean prostate weight was 34.5 (range, 24-54) grams. Gleason scores ranged from 6-7, and the mean Cleveland Clinic Anal Incontinence Score (mean±standard deviation) values were 0.9±1.9 and 0.7±1.2 (p>0.05) before and after surgery, respectively. The Fecal Incontinence Quality of Life Score did not change significantly after surgery. The mean values for anal manometric parameters before and after surgery were, respectively: Resting Pressures of 64±23 mmHg and 65±17 mmHg (p = 0.763), Maximum Squeezing Pressures of 130±41 mmHg and 117±40 mmHg (p = 0.259), High Pressure Zones of 3.0±0.9 cm and 2.7±0.8 cm(p = 0.398), Rectal Sensory Thresholds of 76±25 ml and 71±35 ml (p = 0.539), Maximum Tolerated Rectal Volumes of 157±48 ml and 156±56ml (p = 0.836), and Sphincter Asymmetry Indexes 22.4±9% and 14.4±5% (p = 0.003).

CONCLUSION

There was a significant decrease in the sphincter symmetry index after perineal prostatectomy. With the exception of the sphincter asymmetry index, perineal prostatectomy did not affect anal continence parameters.

Perineal body anatomy in living women: 3-dimensional analysis using thin-slice magnetic resonance imaging

OBJECTIVE

The objective of the study was to describe a framework for visualizing the perineal body's complex anatomy using thin-slice magnetic resonance (MR) imaging.

STUDY DESIGN

Two millimeter thick MR images were acquired in 11 women with normal pelvic support and no incontinence/prolapse symptoms. Anatomic structures were analyzed in axial, sagittal, and coronal slices. Three-dimensional (3-D) models were generated from these images.

RESULTS

Three distinct perineal body regions are visible on MR imaging: (1) a superficial region at the level of the vestibular bulb, (2) a midregion at the proximal end of the superficial transverse perineal muscle, and (3) a deep region at the level of the midurethra and puborectalis muscle. Structures are best visualized on axial scans, whereas craniocaudal relationships are appreciated on sagittal scans. The 3-D model further clarifies interrelationships.

CONCLUSION

Advances in MR technology allow visualization of perineal body anatomy in living women and development of 3-D models that enhance our understanding of its 3 different regions: superficial, mid, and deep.